#include <StringConstants.au3> ; to declare the Constants of StringRegExp
#include <Array.au3> ; UDF needed for _ArrayDisplay and _ArrayConcatenate
Local $sRegex = "(?m)(?<=\btrackingID\b=)\s*[^;\r\n]*"
Local $sString = "ErrorString : trackingID=jskdf-77sdkj-oij4-kerj43-lklfds; key1=lksfjsdkjfkslkdjf;key2=skjfjdkfj43jrkjskd;key4=lksfjsdkjfkslkdjf;key4=skjfjdkfj43jrkjskd;{\"info\":{\"details\":[{\"code\":\"ABC23423\",\"messages\":\"msg:INVALID_ERROR\",\"timeStamp\":\"2019-08-30T15:03:43.668Z\"}],\"$httpStatus\":400},\"status\":400,\"test\":\"ABC2342fdsff3\"" & @CRLF & _
"" & @CRLF & _
"" & @CRLF & _
"" & @CRLF & _
"ErrorString : key1=lksfjsdkjfkslkdjf;key2=skjfjdkfj43jrkjskd;key4=lksfjsdkjfkslkdjf;key4=skjfjdkfj43jrkjskd;{\"info\":{\"details\":[{\"code\":\"ABC23423\",\"timeStamp\":\"2019-08-30T15:03:43.668Z\"}],\"$httpStatus\":400},\"messages\":\"msg:INVALID_ERROR\",\"status\":400,\"test\":\"ABC2342fdsff3\"trackingID=jskdf-77sdkj-oij4-kerj43-lklfds;" & @CRLF & _
"" & @CRLF & _
"" & @CRLF & _
"" & @CRLF & _
"ErrorString : trackingID=jskdf-77sdkj-oij4-kerj43-lklfds; key1=lksfjsdkjfkslkdjf;key2=skjfjdkfj43jrkjskd;key4=lksfjsdkjfkslkdjf;key4=skjfjdkfj43jrkjskd;{\"info\":{\"details\":[{\"code\":\"ABC23423\",\"timeStamp\":\"2019-08-30T15:03:43.668Z\"}],\"status\":400,\"$httpStatus\":400},\"messages\":\"msg:INVALID_ERROR\",\"test\":\"ABC2342fdsff3\""
Local $aArray = StringRegExp($sString, $sRegex, $STR_REGEXPARRAYGLOBALFULLMATCH)
Local $aFullArray[0]
For $i = 0 To UBound($aArray) -1
_ArrayConcatenate($aFullArray, $aArray[$i])
Next
$aArray = $aFullArray
; Present the entire match result
_ArrayDisplay($aArray, "Result")
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for AutoIt, please visit: https://www.autoitscript.com/autoit3/docs/functions/StringRegExp.htm